Reducing power consumption is desirable in most computer systems, and is especially desirable in battery-operated, mobile computer systems (e.g., mobile phones, digital personal assistants, laptop computers) which are provided with limited power supplies. Increasing performance also is desirable in most computer systems, and is especially desirable in mobile systems since they run an increasing number of applications which demand high performance capability from the system hardware. However, a reduction in power consumption generally entails an undesirable reduction in performance. Likewise, an increase in performance generally entails an undesirable increase in power consumption.